JP5481291B2 - Liquid crystal display - Google Patents

Description

  The present invention relates to a liquid crystal display device.

  As backlights for liquid crystal display devices, there are known an edge light method in which a light source such as a light emitting diode is disposed on an end face of a light guide plate and surface light is emitted by the light guide plate, and a direct light type method in which a light source is disposed directly under a liquid crystal panel ing.

  Note that Patent Document 1 discloses a liquid crystal display device in which a plurality of light-emitting components composed of fluorescent tubes are arranged directly below a liquid crystal cell. Patent Document 2 discloses a liquid crystal display device in which one light source is disposed below the liquid crystal shutter.

JP 2009-169324 A Japanese Patent Laid-Open No. 06-301004

  Here, in order to reduce the member cost of the direct type liquid crystal display device, for example, it is conceivable to reduce the number of light sources and make the light sources arranged below the liquid crystal panel sparse.

  However, when the number of light sources arranged on the lower side of the liquid crystal panel is reduced, it becomes difficult to uniformly irradiate the liquid crystal panel with backlight.

  In view of the above problems, an object of the present invention is to provide a liquid crystal display device in which backlight light is evenly irradiated on a liquid crystal panel even when the number of light sources is reduced to reduce costs.

  (1) In view of the above problems, a liquid crystal display device according to the present invention includes a liquid crystal panel having a display area for displaying an image, a linear light-emitting portion arranged below the display area and extending linearly. A diffusion plate disposed between the liquid crystal panel and the linear light emitting unit, and the diffusion plate is formed to be thicker than other portions located below the display area. It has a thick part, The said thick part is formed facing the said linear light emission part, It is characterized by the above-mentioned.

  (2) The liquid crystal display device according to (1), wherein the liquid crystal display device includes an optical sheet disposed between the liquid crystal panel and the linear light emitting unit, the optical sheet, and the diffusion plate. A frame-shaped panel-side frame disposed on the liquid crystal panel side, and a frame-shaped light-emitting portion side frame disposed on the linear light-emitting portion side with respect to the optical sheet and the diffusion plate, The panel side frame and the light emitting unit side frame are arranged with a space therebetween, and the diffusion plate and the optical sheet are inserted and held between the light emitting unit side frame and the panel side frame. At least one of the panel-side frame and the light-emitting portion-side frame may have a convex portion in a portion that holds the thick portion of the diffusion plate.

  (3) In the liquid crystal display device described in (2), the optical sheet is disposed closer to the liquid crystal panel than the diffuser plate, and the diffuser plate has an upper surface formed in a planar shape, The thick part may be formed so as to protrude downward and become thicker than the other part.

  (4) In the liquid crystal display device according to (2), the panel-side frame may include the convex portion in a portion that holds the thick portion of the diffusion plate.

  (5) The liquid crystal display device according to (1), wherein the thick portion is formed so as to gradually rise as it approaches a position facing the center of the linear light emitting portion. Good.

  (6) In the liquid crystal display device according to (2), the thick portion extends along the linear light emitting portion to the interval between the light emitting portion side frame and the panel side frame. It may be a feature.

  (7) In the liquid crystal display device of (2), the convex portion is formed by attaching a resin plate to at least one of the panel-side frame and the light-emitting portion-side frame. It is good.

  (8) In the liquid crystal display device of (2), at least one of the panel-side frame and the light-emitting portion-side frame has the convex portion at a portion that holds the thickest portion of the thick portion. This may be a feature.

  (9) The liquid crystal display device according to (1), wherein the liquid crystal display device includes an optical sheet disposed between the liquid crystal panel and the linear light emitting unit, and the liquid crystal rather than the optical sheet and the diffusion plate. A frame-shaped panel-side frame disposed on the panel side; and a frame-shaped light-emitting unit side frame disposed on the linear light-emitting unit side with respect to the optical sheet and the diffusion plate, and the panel side The frame and the light emitting unit side frame are spaced from each other, and the diffusion plate and the optical sheet are inserted and held between the light emitting unit side frame and the panel side frame, and the diffusion The plate has a bank portion at a position between the panel-side frame and the light-emitting portion-side frame, where a portion facing the linear light-emitting portion is extended, and in the bank portion. Thickness, is thicker than the thick portion may be characterized by.

  ADVANTAGE OF THE INVENTION According to this invention, the liquid crystal display device by which backlight light is uniformly irradiated to a liquid crystal panel can be provided, reducing the number of light sources and suppressing cost.

FIG. 3 is an exploded perspective view illustrating main members of the liquid crystal display device according to the first embodiment. 1 is a schematic plan view of a liquid crystal display device according to Embodiment 1. FIG. It is a figure which shows the mode of the III-III cross section of FIG. It is a figure which shows the mode of the IV-IV cross section of FIG. It is a figure which shows the mode of the VV cross section of FIG. It is a figure which shows the mode of the cross section of the liquid crystal display device concerning Embodiment 2. FIG. It is a figure which shows a mode that the diffuser plate which has a thick part vibrates within a liquid crystal display device. It is a figure which shows a mode that the diffuser plate which has a thick part vibrates within a liquid crystal display device.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[Embodiment 1]
FIG. 1 is an exploded perspective view showing main members of the liquid crystal display device according to Embodiment 1 of the present invention. As shown in the figure, the liquid crystal display device in Embodiment 1 includes a liquid crystal panel LP, a support member S1, an optical sheet OS, a diffusion plate DB, a support member S2, and a linear light emitting portion IL. Composed.

  The liquid crystal panel LP includes a TFT substrate which is a glass substrate on which thin film transistors (TFTs) are formed in a matrix, a counter substrate facing the TFT substrate, and a liquid crystal layer sandwiched therebetween, and The upper polarizing plate and the lower polarizing plate have transmission axes orthogonal to each other.

  The light (backlight) irradiated to the liquid crystal panel LP becomes linearly polarized light when passing through the lower polarizing plate, and the polarization direction is controlled for each pixel according to the crystal state of the liquid crystal layer, and according to the polarization state. Then, it is transmitted through or shielded from the upper polarizing plate. The liquid crystal panel LP has a display area for displaying an image. In the display region, a plurality of pixels are arranged in a matrix, and the crystal state of the liquid crystal layer is controlled by a thin film transistor in each pixel.

  The linear light emitting portion IL is disposed below the display area of the liquid crystal panel LP, and functions as a light source of backlight light that irradiates the display area. The linear light emitting portion IL of the present embodiment is a cold cathode tube and is a light emitter that emits light linearly. As shown in FIG. 1, the linear light emitting portion IL is arranged at the center of the display area of the liquid crystal panel LP so as to be substantially parallel to the longitudinal direction.

  The diffusion plate DB is disposed between the linear light emitting portion IL and the liquid crystal panel LP, diffuses light from the linear light emitting portion IL, and irradiates the liquid crystal panel LP. The diffusion plate DB of the present embodiment is configured by randomly mixing micro-sized spheres having a refractive index different from the material of the resin plate in a resin plate such as acrylic. Therefore, the degree to which the diffusion plate DB diffuses light increases according to its thickness. In particular, the diffusion plate DB of the present embodiment has a thick portion DBa as shown in FIG. 1, and the thick portion DBa is disposed at a position facing the linear light emitting portion IL. Details of the thick part DBa will be described later.

  The optical sheet OS of the present embodiment is disposed between the diffusion plate DB and the liquid crystal panel LP, and has a plurality of microlenses on the surface on the liquid crystal panel LP side. The optical sheet OS irradiates the backlight light toward the liquid crystal panel LP while condensing the light from the diffusion plate DB in the front direction (direction perpendicular to the display area).

  The support member S1 is a resin member that supports the liquid crystal panel LP from below. The support member S1 of this embodiment includes a panel-side frame F1 having a frame shape, and the panel-side frame F1 supports the liquid crystal panel LP from the lower side while fixing the outer periphery of the liquid crystal panel LP with an adhesive member or the like.

  The support member S2 is a resin member that supports the support member S1 from below. The support member S2 of the present embodiment has a light emitting part side frame F2 having a frame shape and a box-shaped part that accommodates the linear light emitting part IL, and the diffusion plate DB and the optical sheet OS include a panel. It is held between the side frame F1 and the light emitting unit side frame F2.

  Next, FIG. 2 is a schematic view of the liquid crystal display device according to this embodiment as viewed from above. The liquid crystal panel LP (liquid crystal display device) of the present embodiment is arranged so that the horizontal direction is the longitudinal direction and the vertical direction is the short direction as viewed from the observer. As shown in the figure, the display area DP of the liquid crystal panel LP is arranged at a position inside the panel-side frame F1.

  As shown in FIG. 2, the linear light emitting portion IL is linear along the longitudinal direction of the liquid crystal panel LP, and is disposed at the center in the short direction of the liquid crystal panel LP. In this embodiment, the thick portion DBa of the diffusion plate DB (not shown in FIG. 2) is formed in a strip shape along the direction in which the linear light emitting portion IL extends, and in the longitudinal direction parallel to the linear light emitting portion IL. Stretched.

  Here, FIG. 3 is a diagram schematically showing the state of the III-III cross section in FIG.

  As shown in FIG. 3, the diffusion plate DB has a thick portion DBa formed thicker than other portions located below the display region DP. In the diffusing plate DB, a large amount of light is incident on a position facing the linear light emitting portion IL. However, the thick portion DBa is arranged so as to face the linear light emitting portion IL. Light from the light emitting portion IL is efficiently diffused upward and downward in the lateral direction. As a result, the backlight light is uniformly applied to the liquid crystal panel LP.

  In addition, the diffusion plate DB of the present embodiment has an upper surface formed in a planar shape, and on the lower surface, the thick plate portion DBa is formed by protruding on the side where the linear light emitting portion IL is disposed. As shown in FIG. 3, the thick portion DBa is formed wider than the linear light emitting portion IL and is disposed so as to face the linear light emitting portion IL. Further, the thick portion DBa of the present embodiment is formed so that the thickness gradually increases as it approaches the center of the linear light emitting portion IL, and the portion facing the center is formed to be thickest. By forming the thickness gradually changing in this way, a rapid change in the distribution of the backlight light applied to the liquid crystal panel LP can be suppressed.

  Here, the panel side frame F1 and the light emitting unit side frame F2 that hold the diffusion plate DB and the like will be described in detail.

  The diffusion plate DB and the optical sheet OS are held with a clearance between the panel side frame F1 and the light emitting unit side frame F2 in order to prevent optical characteristics from changing due to the occurrence of distortion caused by thermal expansion. . That is, the diffusing plate DB and the optical sheet OS are in a state where they are not completely fixed while allowing dimensional changes due to different thermal expansion coefficients.

  Specifically, the panel side frame F1 and the light emitting unit side frame F2 are arranged at intervals, and the diffusion plate DB and the optical sheet OS are inserted and held between the intervals. As shown in FIG. 3, the diffusion plate DB and the optical sheet OS are held with a certain amount of clearance secured in the in-plane direction and the thickness direction, and the panel side frame F1 and the light emitting unit side frame F2 are The gaps are arranged so as to be wider than the total thickness of the thick part DBa and the optical sheet OS.

  However, when the diffusion plate DB is held with clearance as described above, the diffusion plate DB may vibrate due to the thick portion DBa. 7A and 7B are diagrams for explaining how the diffusion plate DB vibrates. The diffusion plate DB and the optical sheet OS have different natural frequencies. When relatively high-frequency vibration is applied to the liquid crystal display device, the optical sheet OS does not vibrate so much and has a thick portion DBa. The plate DB may vibrate greatly.

  7A and 7B show a portion of the diffusion plate DB and the optical sheet OS that is inserted between the panel side frame F1 and the light emitting unit side frame F2, and specifically corresponds to IV-IV in FIG. The state of the cross section of the part to perform is shown. As shown in the figure, when the diffusing plate DB vibrates greatly, the optical sheet OS repeatedly comes into contact with the panel-side frame F1, and the optical sheet OS is damaged or a piece of the optical sheet OS is damaged. May occur and adversely affect the image.

  In the present embodiment, in view of the above-described possibility, the convex portion Pr is arranged to suppress the vibration of the diffusion plate DB. The convex portion Pr is disposed on at least one of a portion holding the thick portion DBa of the panel side frame F1 and a portion holding the thick portion DBa of the light emitting portion side frame F2, and thereby the thickness generated at a relatively high frequency. The vibration of the portion DBa is reduced, and the generation of scratches and fragments on the optical sheet OS is suppressed.

  4 and FIG. 5 are views showing the states of the IV-IV section and the VV section in FIG. 2, respectively. The convex part Pr of this embodiment is a resin plate made of a PET film (polyester film), and is affixed to a part of the panel side frame F1 that holds the thick part DBa with a double-sided tape. As shown in FIG. 2, the convex portions Pr are arranged at two locations corresponding to the center in the short direction of the liquid crystal panel LP, and are arranged on an extension of the linear light emitting portion IL. As a position where the convex part Pr is arranged, it is desirable to arrange it at a part of the panel side frame F1 and the light emitting part side frame F2 that holds the thickest part of the thick part DBa.

  That is, the panel side frame F1 and the light emitting unit side frame F2 are arranged so that the surfaces facing the diffusion plate DB are substantially parallel with a predetermined interval, and the thick portion DBa is inserted and held. The portion to be formed is formed to be a gap narrower than the predetermined interval. Thereby, the vibration of the thick part DBa is suppressed. Further, the support member S1 of the present embodiment is a member that maintains the interval between the panel side frame F1 and the light emitting unit side frame F2 and fixes them. Further, the support member S1 is also a member having a wall surface that is continuously formed with respect to two facing surfaces facing the diffusion plate DB and the like of the panel side frame F1 and the light emitting unit side frame F2. The diffusing plate DB and the optical sheet OS are held with their outer peripheral portions covered with the two opposing surfaces and the wall surface. The convex part Pr may be formed in both the panel side frame F1 and the light emitting part side frame F2.

  Moreover, in this embodiment, although the convex part Pr is made into the resin board, the convex part Pr may be integrally shape | molded with the same material as the panel side frame F1, for example, and is formed with materials other than a resin board. Also good. Further, although the convex portion Pr is formed in a plate shape, an inverted T-shaped member may be formed so as to protrude with respect to the panel-side frame F1 or in consideration of contact with the optical sheet OS or the like. A rounded shape without corners may be used. Further, the convex portion Pr may be formed of an elastic buffer member such as rubber in order to absorb an impact when the optical sheet OS and the diffusion plate DB collide with each other.

[Embodiment 2]
In the first embodiment, in order to suppress the vibration of the diffusion plate DB having the thick portion DBa, the convex portion Pr is formed in the portion that holds the thick portion DBa of the panel side frame F1. However, in the present embodiment, as shown in FIG. 6, the diffusing plate DB has a bank portion Bu instead of forming the convex portion Pr. Except for this point, the liquid crystal display device of the second embodiment is substantially the same as the liquid crystal display device of the first embodiment, and the description of the same points is omitted.

  The bank part Bu is located between the panel side frame F1 and the light emitting part side frame F2, and is located at a position that is an extension of the linear light emitting part IL, and the bank part Bu of the diffusion plate DB in the bank part Bu. The thickness is even thicker than the thick part DBa on the lower side of the display area DP. Thereby, the clearance of the thickness direction of the part holding the thick part DBa becomes small, and the vibration produced by the thick part DBa is suppressed.

  In the second embodiment, as shown in FIG. 6, the bank portion Bu is formed to protrude from the lower surface of the diffusion plate DB, but may be formed to protrude from the upper surface. In the case where the bank portion Bu is formed so as to protrude from the upper surface, the optical sheet OS may be formed with a notch that avoids the bank portion Bu. In the second embodiment, the bank portion Bu is integrally formed with the diffusion plate DB, but may be formed by attaching another member.

  In each of the above embodiments, the linear light-emitting portion IL is a cold cathode tube, but the linear light-emitting portion IL may be composed of, for example, other types of fluorescent tubes, or emit light in a linear region. A diode may be arranged.

  Note that, as in each of the embodiments described above, it is preferable that one optical sheet OS is disposed on the upper side of the diffusion plate DB. However, a plurality of optical sheets OS may be arranged, or may be arranged below the diffusion plate DB, not on the upper side. In any case, the vibration of the diffusion plate DB having the thick portion DBa is suppressed by the arrangement of the convex portion Pr, and the optical sheet OS is hardly damaged as in each of the above embodiments. Become. Further, the optical sheet OS may have a notch for avoiding the convex portion Pr and the bank portion Bu.

  In each of the above embodiments, one linear light emitting portion IL is arranged so as to be linear in the lateral direction when viewed from the observer side. However, the plurality of linear light emitting portions IL may be arranged linearly in the lateral direction. Further, one or a plurality of linear light emitting portions IL may be arranged so as to be linear in the vertical direction. Here, for example, in the case of a large liquid crystal display device, it is preferable that the linear light emitting portions IL are arranged at a plurality of locations. In any case, the thick portion DBa is formed so as to face at least one of the one or more linear light emitting portions IL so that the liquid crystal panel LP is uniformly irradiated with light. become.

  In each of the above embodiments, the thick portion DBa is formed so as to protrude downward. However, the thick portion DBa may be formed so as to protrude upward, or may be formed so as to protrude on both the upper and lower sides and become thick. In either case, the light emitted from the linear light emitting portion IL can be efficiently diffused, and vibration due to the thick portion DBa is generated.

  In each of the above-described embodiments, as shown in FIG. 3 and the like, portions other than the thick portion DBa on the lower surface of the diffusion plate DB are formed in a planar shape, and the thick portion DBa is gradually raised. Formed. In each of the embodiments described above, the width of the thick portion DBa (the length in the vertical direction in FIG. 2) is preferably 20% or more and 40% or less of the width of the diffusion plate DB. The thickest part of the thick part DBa is preferably about twice the thickness of the part other than the thick part DBa.

  As in the above embodiments, the thick portion DBa extends from the portion of the diffusion plate DB facing the linear light emitting portion IL to a position between the panel side frame F1 and the light emitting portion side frame F2. In addition, it is desirable that the convex portion Pr or the like is disposed at the extended position of the thick portion DBa. However, the thick part DBa does not necessarily extend to a position between the panel side frame F1 and the light emitting part side frame F2. Even in such a case, the light emission from the linear light emitting portion IL can be efficiently diffused, and further, the vibration due to the thick portion DBa is also generated. Therefore, the convex portion Pr is arranged as in the above embodiment, etc. Vibration is suppressed.

  In each of the above embodiments, the liquid crystal panel LP is fixed by the panel side frame F1, and the support member S1 is supported by the light emitting unit side frame F2. However, the liquid crystal panel LP may be fixed by a member different from the panel side frame F1, or the support member S1 may be attached to and supported by a member different from the light emitting unit side frame F2. The support member S1 has a panel side frame F1, and is a member that maintains and fixes the space between the panel side frame F1 and the light emitting unit side frame F2. However, the member that maintains and fixes the interval may not be the support member S1, and may be a member different from the panel side frame F1. Moreover, the panel side frame F1 and the light emission part side frame F2 may be integrally formed by one common member.

  In addition, the present invention may be applied to an IPS (In Plane Switching) type liquid crystal display device, or to other types of liquid crystal display devices such as a VA (Vertical Alignment) type and a TN (Twisted Nematic) type. Needless to say, you can.

  The present invention is not limited to the above-described embodiments, and various modifications are possible, and it goes without saying that the above-described embodiments may be combined. In addition, for example, the configuration described in the embodiment can be replaced with a substantially the same configuration, a configuration that exhibits the same operational effects, or a configuration that can achieve the same purpose.

  LP liquid crystal panel, S1, S2 support member, OS optical sheet, DB diffuser plate, DBa thick part, Bu bank part, IL linear light emitting part, Pr convex part, DP display area, F1 panel side frame, F2 light emitting part side flame.

Claims (8)

A liquid crystal panel having a display area for displaying an image;
A linear light-emitting portion disposed below the display area and extending linearly;
An optical sheet and a diffusing plate disposed between the liquid crystal panel and the linear light emitting unit;
A frame-like panel-side frame disposed closer to the liquid crystal panel than the optical sheet and the diffusion plate;
A frame-like light emitting part side frame disposed on the linear light emitting part side with respect to the optical sheet and the diffusion plate ,
The diffusion plate has a thick portion formed so as to be thicker than other portions located below the display area,
The thick part is formed to face the linear light emitting part ,
The panel side frame and the light emitting unit side frame are arranged facing each other and spaced apart from each other,
At least one of the panel-side frame and the light-emitting portion-side frame is in a portion that holds the thick portion of the diffusion plate in a facing region where the panel-side frame and the light-emitting portion-side frame face each other. Has a convex part,
The distance between the opposing regions is wider than the sum of the thickness of the diffuser plate where the thick portion is formed, the thickness of the optical sheet, and the thickness of the convex portion,
The optical sheet and the diffusing plate are held by inserting respective end portions into the facing region .
A liquid crystal display device characterized by the above. The liquid crystal display device according to claim 1 ,
The optical sheet is disposed closer to the liquid crystal panel than the diffusion plate,
The diffusion plate is formed with a flat upper surface,
The thick part is formed so as to protrude downward and become thicker than the other part.
A liquid crystal display device characterized by the above. The liquid crystal display device according to claim 1 ,
The panel-side frame has the convex portion in a portion that holds the thick portion of the diffusion plate in the facing region .
A liquid crystal display device characterized by the above. The liquid crystal display device according to claim 1,
The thick portion is formed so as to gradually rise as it approaches a position facing the center of the linear light emitting portion.
A liquid crystal display device characterized by the above. The liquid crystal display device according to claim 1 ,
The thick portion extends along the linear light emitting portion to the inside of the facing region of the light emitting portion side frame and the panel side frame.
A liquid crystal display device characterized by the above. The liquid crystal display device according to claim 1 ,
The convex part is formed by attaching a resin plate to at least one of the panel side frame and the light emitting part side frame.
A liquid crystal display device characterized by the above. The liquid crystal display device according to claim 1 ,
At least one of the panel side frame and the light emitting unit side frame has the convex portion in a portion that holds the thickest portion of the thick portion in the facing region .
A liquid crystal display device characterized by the above. A liquid crystal panel having a display area for displaying an image;
A linear light-emitting portion disposed below the display area and extending linearly;
Wherein disposed between the liquid crystal panel and the linear light emitting portion, and the optical sheet and the diffusion plate,
A frame-like panel-side frame disposed closer to the liquid crystal panel than the optical sheet and the diffusion plate;
A frame-like light emitting part side frame disposed on the linear light emitting part side with respect to the optical sheet and the diffusion plate,
The diffusion plate has a thick portion formed so as to be thicker than other portions located below the display area,
The thick part is formed to face the linear light emitting part,
The panel side frame and the light emitting unit side frame are arranged facing each other and spaced apart from each other,
The diffusion plate has a bank portion at a position where a portion facing the linear light emitting portion is extended in a facing region where the panel side frame and the light emitting portion side frame face each other .
The distance between the opposing regions is wider than the sum of the thickness of the thick plate portion and the bank portion of the diffuser plate and the thickness of the optical sheet,
The thickness of the portion where the bank portion is formed in the diffusion plate is thicker than the thickness of the portion where the thick portion is formed in the diffusion plate,
The optical sheet and the diffusing plate are held by inserting respective end portions into the facing region .
A liquid crystal display device characterized by the above.

Images